window.addEventListener("DOMContentLoaded", initializeFundraisingBar);

function initializeFundraisingBar() {
	const VISIBILITY_COVERAGE_FRACTION = 0.5;

	let loaded = false;

	const fundraising = document.querySelector("[data-fundraising]");
	if (!fundraising) return;
	const bar = fundraising.querySelector("[data-fundraising-bar]");
	const dynamicPercent = fundraising.querySelector("[data-fundraising-percent] [data-dynamic]");
	const dynamicGoal = fundraising.querySelector("[data-fundraising-goal] [data-dynamic]");
	if (!(fundraising instanceof HTMLElement && bar instanceof HTMLElement && dynamicPercent instanceof HTMLElement && dynamicGoal instanceof HTMLElement)) return;

	const setFundraisingGoal = async () => {
		const request = await fetch("https://graphite.art/fundraising-goal");
		/** @type {{ percentComplete: number, targetValue: number }} */
		const data = await request.json();

		fundraising.classList.remove("loading");
		bar.style.setProperty("--fundraising-percent", `${data.percentComplete}%`);
		dynamicPercent.textContent = `${data.percentComplete}`;
		dynamicGoal.textContent = `${data.targetValue}`;

		loaded = true;
	};
	new IntersectionObserver(
		(entries) => {
			entries.forEach((entry) => {
				if (!loaded && entry.intersectionRatio > VISIBILITY_COVERAGE_FRACTION) setFundraisingGoal();
			});
		},
		{ threshold: VISIBILITY_COVERAGE_FRACTION },
	).observe(fundraising);
}
